Marc-André worked on improving API clarity in the dotnet/aspire repository by refining the naming conventions for build secrets handling. He implemented a non-functional rename, changing the API reference from WithSecretBuildArg to WithBuildSecret, which enhanced discoverability and consistency for developers using the API. This update was carefully designed to maintain backward compatibility, ensuring that existing workflows remained unaffected. His work focused on C# programming and API development, with attention to robust error handling practices. The scope of the contribution was targeted and precise, addressing a specific usability concern rather than introducing new features or fixing bugs during the period.